Unlike many game, Starcraft 2 has tons of replay value, I bought it in spring 2010 and I still play it regularly when I have the time, along with a few others.
Another good pay what you want pack of indie games is up for sale again.
These include
Crayon Physics Deluxe
Cogs
VVVVVVVVV
Hammerfight
And Yet It Moves
The lowest you can pay for these is $.01 so there is really no reason to not get them (although proceeds go to charity so I encourage you to donate more if you can :P)
Also they are usually redeemable on Steam, meaning they will give you a code and you enter it in Steam and it will give you all the games on Steam.